Medical instrument

ABSTRACT

The invention relates to a medical instrument with a shaft ( 2 ), a handle ( 3 ) mounted on the proximal end of the shaft ( 2 ), and a tool ( 4 ) mounted on the distal end of the shaft ( 2 ) and capable of being activated by means of the handle ( 3 ), where the handle ( 3 ) and the tool ( 4 ) are in active connection by means of at least one activation rod ( 6 ). To make it possible for the tool ( 4 ), in particular as a one-way tool, to be secured simply and rapidly on the activation rod ( 6 ), the invention proposes that the tool ( 4 ) should have a tool shaft ( 7 ) for securing it to the activation rod ( 6 ) and that the tool shaft ( 7 ) and the activation rod ( 6 ) in order to be secured to one another should have protuberances ( 8 ) and/or recesses ( 9 ), which can be engaged, at least partially as a form-locking connection, with corresponding recesses ( 9 ) or protuberances ( 8 ) of the other respective component ( 6, 7  or  7, 6 ).

[0001] This application claims priority from pending German PatentApplication No. 02 020 720.5 filed on Sep. 14, 2002.

FIELD OF THE INVENTION

[0002] The invention relates to a medical instrument with a shaft, ahandle mounted on the proximal end of the shaft, and a tool mounted onthe distal end of the shaft and capable of being activated by means ofthe handle, where the handle and the tool are in active connection bymeans of at least one activation rod.

[0003] Conventional medical instrument are frequently used in practiceas gripping, securing, and/or cutting tools. Thus, the jaw members canhave blades for severing tissue or blunt surfaces for holding severedtissue, for instance, or stanching blood vessels.

[0004] In order to make the most flexible possible use of a medicalinstrument of this kind, on the one hand, and, on the other, tofacilitate cleaning of the instrument, the known practice is to connectthe tool detachably with the activation rod. The known connectionsbetween tool and activation rod, however, had the disadvantage that, asis known from EP 0577423 B1, they are of very expensive construction asscrew-in or nesting connections, and thus simple, rapid, and thuscost-efficient tool replacement is not possible with these knowninstruments.

[0005] A conventional medical instrument is known from U.S. Pat. No.5,496,347. In this known instrument, the activation rod is secureddirectly on the jaw members of the tool. For this purpose, the distalend of the activation rod has recesses into which cams configured on thejaw members engage. In order to secure the connection of the activationrod with the jaw members in the radial direction of the shaft, on theone hand the activation rod is mounted between the two jaw members andon the other hand the distal end of the shaft is configured so that theactivation rod and the jaw members in this coupling area are surroundedby a housing, which is arranged inside the hollow shaft and in additionserves as a guide for the activation rod.

[0006] This known construction allows the tool to be secured on theactivation rod without screwing connections; however, the complexity ofinstallation—especially because of the use of the additional housing andthe connection of the activation rod with the individual jaw members ofthe tool—is so great that, here too, simple, rapid, and thuscost-effective tool replacement is not possible with this instrument.Consequently it is the aim of the invention to design a medicalinstrument of the aforementioned type in such a way that the tool can besecured, especially as a one-way tool, simply and rapidly on theactivation rod.

[0007] The aim is fulfilled according to the invention in that the toolhas a tool shaft for purposes of securing it to the activation rod, andthat the tool shaft and the activation rod, for purposes of securingthem to one another, have protuberances and/or recesses, which can beengaged, at least partially as a form-locking connection, withcorresponding recesses or protuberances of the other respectivecomponent.

[0008] Thanks to the invention's design of the coupling areas of thetool and activation rod, it is possible for the first time to secure thecomponents that are to be joined together without additional securingelements, essentially by means of a socket connection. The flexibilityof the instrument to be used with various tools is consequentlyincreased because the protuberances and/or recesses for securing theactivation rod to the tool are configured on a tool shaft of the tool.

[0009] To ensure the widest possible use of the inventive medicalinstrument, according to a preferred embodiment it is proposed that thetool should be able to be secured to the activation rod in such a waythat forces in the longitudinal direction of the activation rod and/ortorsion forces can be transmitted to the tool.

[0010] The tool and activation rod are connected preferably by means ofa movement that is essentially perpendicular to the longitudinal axis ofthe activation rod, whereby this motion can be executed as an insertionmotion in the direction perpendicular to the longitudinal axis of theactivation rod or as a rotating motion around an axis perpendicular tothe longitudinal axis of the activation rod.

[0011] It is also proposed with the invention that the tool should bedetachably fixable to the tool. In this configuration, the tool shaftfor instance can be used as an adapter in order to bring various toolswith the adapter that has an identical activation rod connection intoconnection with the activation rod.

[0012] According to a preferred embodiment of the invention, theactivation rod and the tool shaft are configured to have an essentiallyround cross-section. This configuration is particularly advantageouswhen torsion forces are to be transferred to the tool.

[0013] According to a first practical embodiment with essentially roundcross-section of the activation rod and the tool shaft, in the area ofthe distal end of the round activation rod at least on one side atangential leveling is configured on the activation rod in such a waythat the distal end of the activation rod also has a head area thatextends beyond the leveling in radial direction. The proximal area ofthe tool shaft thus has an overlapping for receiving the head area ofthe activation rod as well as a recess corresponding with the tangentialleveling of the activation rod.

[0014] While it is possible, with the aforementioned embodiment, toconfigure the leveling asymmetrically, it is proposed according to asecond alternative embodiment that the tangential leveling of theactivation rod should be configured as a center rod leveled from twoopposite sides and the corresponding recess on the tool shaft isconfigured as a radial slit.

[0015] It is further proposed with the invention that the activation rodand the tool can be coupled with one another by means of at least onestud running diagonally to the instrument longitudinal axis, where thestud is configured either on the activation rod or on the tool shaft andengages in a corresponding recess in the tool shaft or in the activationrod.

[0016] Use of the stud to connect the activation rod with the tool canthus be considered in addition or as an alternative to the configurationof the overlapping and of the head area.

[0017] It is, finally, proposed with the invention that a spring elementshould be included in order to transmit pulling or pushing forces in thecoupling area between the activation rod and the tool. Besides thepossibility of using the spring power of the spring element, forinstance in order to open the tool in applying pushing pressure, thespring force reinforces the form-locking link of the activation rod andtool shaft components.

[0018] Additional characteristics and advantages of the invention can beseen from the following description of the associated illustrations, inwhich three embodiments of an inventive medical instrument are depictedschematically as examples. The illustrations are as follows:

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1A schematic lateral view of an inventive medical instrument

[0020]FIG. 2a A perspective lateral view of an activation rod and a toolaccording to a first embodiment of the invention in assembled condition.

[0021]FIG. 2b A view according to FIG. 2a, but depicting the activationrod and the tool in a position detached from one another.

[0022]FIG. 3A view according to FIG. 2b, depicting a second embodimentof the invention

[0023]FIG. 4A view according to FIG. 2b, depicting a third embodiment ofthe invention

DETAILED DESCRIPTION OF THE DRAWINGS

[0024] The illustration in FIG. 1 shows a lateral view of a medicalinstrument 1, whose power transmission mechanism can be used in manyways, such as for punching, cutting, as a needle holder, to secureinstruments, and so on.

[0025] The illustrated medical instrument 1 consists essentially of ahollow shaft 2 having on its proximal end a handle 3 which consists of arigid gripping member 3 a and a gripping member 3 b that can be rotatedin relation to the rigid gripping member 3 a. The distal end of theshaft 2 has a tool 4 which is made up of two jaw members 4 a and 4 bthat can rotate with respect to one another around a common rotationpoint 5.

[0026] As can be seen from the views in FIGS. 2a to 4 in connection withthe composite view of FIG. 1, the jaw members 4 a and 4 b of the tool 4and the rotatable gripping member 3 b of the handle 3 are connected withone another by means of an activation rod 6 in such a way that the jawmembers 4 a and 4 b can be moved from the closed position (striped areain FIG. 1) into the open position (dotted section in FIG. 1) or viceversa by displacement of the gripping member 3 b. The respectiveresulting position of the rotatable gripping member 3 b is also stripedin FIG. 1 (indicating the closed position) and dotted (for the openposition).

[0027] The illustrations in FIGS. 2a to 4 also show that the activationrod 6 is not directly secured to the tool 4, but rather to a tool shaft7, which in the illustrated embodiments is detachably connected with thetool 4 and in direct active connection with the jaw members 4 a and 4 bof the tool 4.

[0028] To connect the activation rod 6 with the tool shaft 7, theillustrated embodiments indicate, both on the activation rod 6 and onthe tool shaft 7, protuberances 8 and recesses 9 which correspond withcorresponding protuberances 8 and recesses 9 of the other respectivecomponent (6, 7 or 7, 6) in such a way that they can be brought togetherin form-locking engagement. In the illustrated embodiments, thismutually corresponding configuration of the protuberances 8 and recesses9 can be seen especially in FIG. 2a, which shows a continuous roundcross-section of activation rod 6 and tool shaft 7 when they are joinedtogether. The activation rod 6 and the tool shaft 7 can also, of course,have cross-section shapes that are non-round and/or differ from oneanother.

[0029] In the embodiments illustrated in FIGS. 2a to 4, the recesses 9on the activation rod 6 are formed by tangential levelings which areconfigured on two opposite sides on the activation rod 6 in such a waythat the activation rod in the area of this leveling consists only of anarrow middle stud 9 a. The distal end of the activation rod 6 forms ahead area 8 a which overhangs the middle stud 9 a in radial directionand forms a protuberance 8.

[0030] To receive the middle stud 9 a as well as the head area 8 a ofthe activation rod 6, on the tool shaft 7 a radial slit is configured asa recess 9 and an overlapping 8 b is configured as a protuberance 8. Ascan be seen from FIG. 2a, the respective protuberances 8 and recesses 9of the activation rod 6 and tool shaft 7, when joined together, blendtogether in such a way that they are interlocking in a form-lockingconnection.

[0031] Alternatively to the illustrated embodiments, in which the recess9 is configured on the activation rod 6 as a symmetrical two-sidedleveling of the activation rod 6 forming the middle stud 9 a, it is alsopossible of course to perform the leveling asymmetrically on just oneside or on both sides to strongly varying degrees. The middle stud 9 acan thus, as shown, be four-sided but can for instance have likewise across-section tapering in the insertion direction. It is also possiblethat the cross-section of the middle stud 9 a changes in the axialdirection.

[0032] The second embodiment shown in FIG. 3 differs from the one inFIG. 2b in that a stud 10 is also arranged in the tool shaft 7 runningdiagonally to the instrument longitudinal axis, which stud 10 engages ina corresponding recess 11 in the activation rod 6. In the illustratedembodiment the stud 10 is mounted in a hole 12 bored in the tool shaft7. An alternative possibility is to install the stud 10 on theactivation rod 6 and to configure the corresponding recess 11 on thetool shaft 7, so that it is also possible in both cases to configure thestud 10 as a single unit with the activation rod 6 or the tool shaft 7.

[0033] The third embodiment, illustrated in FIG. 4, differs from the oneFIG. 2b in that a spring element 13 is mounted in the coupling areabetween the activation rod 6 and the tool 4. The spring element 13,sketched only as an example, can serve, for instance in applying pushingpressure, to open the tool 4 by spring action, or else to reinforce theform-locking joining of the components, i.e. activation rod 6 and toolshaft 7. If the spring element 13 is mounted between the tool 4 and thetool shaft 7, the spring element 13 can cause an activation of the tool4 entirely in a single direction (opening or closing). The othercorresponding motion (closing or opening) can then be produced by theactivation of the activation rod 6.

[0034] In particular in the configuration of the coupling area betweenthe activation rod 6 and the tool 4 with a spring element 13, it ispossible to dispense with the head area 8 a shown in FIGS. 2a to 4 onthe activation rod 6.

[0035] In this case no pulling force can be transmitted to the tool 4 bymeans of the activation rod 6, but only pushing and torsion forces. Thepulling forces in this embodiment can be assumed by the spring element13, whose spring force closes the tool 4 or whose spring force must beovercome by means of the pushing force applied by means of theactivation rod 6 to open the tool 4.

[0036] Of course, construction solutions are also possible in which apulling force is applied by means of the activation rod 6 and thepushing force is produced by the spring power of the spring element 13.

[0037] The medical instrument 1 is activated as follows: First, from theseparated starting position illustrated in FIG. 2b, the activation rod 6and the tool shaft 7, by means of a motion essentially perpendicular tothe longitudinal axis of the activation rod 6, are brought intoengagement with one another by matching the reciprocal protuberances 8and recesses 9 so as to produce the joined configuration illustrated inFIG. 2a.

[0038] Then the activation rod 6 with the proximal end in front isintroduced into the hollow shaft 2. To connect the activation rod 6 withthe rotatable gripping member 3 b of the handle 3, on the proximal endof the activation rod 6 a toggle head 14 is arranged which can beinserted to engage with a corresponding spherical recess (notillustrated) on the gripping member 3 b.

[0039] For secure action of the gripping members 3 a, 3 b of the handle3, the handles have finger loops 3 c on their free ends. In theillustrated embodiment the gripping member 3 b can be rotated around arotation axis 15 with respect to the other, rigid gripping member 3 a.

[0040] Through the coupling of the rotatable gripping member 3 b by theactivation rod 6 with the tool 4, the jaw members 4 a, 4 b of the tool 4open and close.

[0041] Thanks to the simple coupling of the activation rod 6 on the tool4 or the tool shaft 7 by the formation of the protuberances 8 andrecesses 9, new tools 4 can be especially simply and quickly secured onthe activation rod 6, so that the use of one-time tools is particularlyfacilitated.

[0042] The coupling of the activation rod 6 on the tool 4 or tool shaft7 is, in addition, configured in such a way that forces can betransmitted in longitudinal direction of the activation rod 6 andtorsion forces can be transmitted on the tool 4.

[0043] Key

[0044]1 Medical instrument

[0045]2 shaft

[0046]3 handle

[0047]3 a rigid gripping member

[0048]3 b rotatable gripping member

[0049]3 c finger loops

[0050]4 tool

[0051]4 a jaw member

[0052]4 b jaw member

[0053]5 rotation point

[0054]6 activation rod

[0055]7 tool shaft

[0056]8 protuberance

[0057]9 recess

[0058]9 a middle stud

[0059]9 b slid

[0060]10 stud

[0061]11 recess

[0062]12 bore hole

[0063]13 spring element

[0064]14 toggle head

[0065]15 axis of rotation

What is claimed is:
 1. Medical instrument with a shaft (2), a handle (3)mounted on the proximal end of the shaft (2), and a tool (4) mounted onthe distal end of the shaft (2) and activated by the handle (3), wherethe handle (3) and the tool (4) are in active connection by means of atleast one activation rod (6) and the tool (4) can be secured detachablyby means of a tool shaft on the activation rod (6), for which purposethe tool shaft (7) and the activation rod (6) have protuberances (9)and/or recesses (9), which can be joined in a form-locking connection,at least partially, with corresponding recesses (9) or protuberances (8)of the other respective component (6, 7 or 7, 6) wherein the recesses(9) and protuberances (8) corresponding to one another are configured insuch a way that the tool (4) and the activation rod (6) can be broughtinto engagement with one another by means of a movement exclusively inone direction essentially perpendicular to the longitudinal axis of theactivation rod (6).
 2. Medical instrument according to claim 1, whereinthe tool (4) can be secured to the activation rod (6) in such a way thatforces can be transmitted in the longitudinal direction of theactivation rod (6) and/or torsion forces can be transmitted to the tool(4).
 3. Medical instrument according to either of claims 1 or 2, whereinthe tool (4) and the activation rod (6) can be connected with oneanother by means of a motion essentially perpendicular to thelongitudinal axis of the activation rod (6).
 4. Medical instrumentaccording to at least one of claims 1 to 3, wherein the activation rod(6) and the tool shaft (7) are configured as essentially round incross-section.
 5. Medical instrument according to claim 4, wherein inthe area of the distal end of the round activation rod (6) at least onone side a tangential leveling is formed on the activation rod (6) insuch a way that the distal end of the activation rod (6) further has ahead area (8 a) overhanging the leveling in radial direction and theproximal area of the tool shaft (7) has an overlap (8 b) for receivingthe head are (8 a) of the activation rod (6) and a recess correspondingto the tangential leveling of the activation rod (6).
 6. Medicalinstrument according to claim 5, wherein the tangential leveling of theactivation rod (6) is configured as a middle stud (9 a) leveled from twoopposite sides and the corresponding recess on the tool shaft (7) isconfigured as a radial slit (9 b).
 7. Medical instrument according to atleast one of claims 1 through 6, wherein the activation rod (6) and thetool (4) can be coupled to one another by means of at least one stud(10) running diagonally to the instrument longitudinal axis, where thestud (10) on the one hand is stored in a hold (12) bored in theactivation rod (6) or in the tool shaft (7) and on the other handengages in a corresponding recess (11) in the tool shaft (7) or in theactivation rod (6).
 8. Medical instrument according to at least one ofclaims 1 to 7, wherein, for the transmission of pulling or pushingforces in the coupling area, a spring element (13) is placed between theactivation rod (6) and the tool (4).
 9. Medical instrument according toclaim 8, wherein the tool (4) can be activated by means of the springelement (13).